Alkylation of aromatic hydrocarbons



March 20, 1951 H. .1. PAsslNo ALKYLATION 0F AROMATIC 'HYDROCARBONSOriginal Filed Oct. 22, 1942 HERBERT J. PASS/No E. LM

ATZ'E/YEYS Patented Mar. `20, 1951 UNITED' STATES FFICE ALKYLATIDN FAROMATG- HYDROCAR'B'0NS' Herbert J. Passino, Englewo0d,Y.-J.f,assigfnorfto The M. W. Kellogg Company, Jersey City, NQ J., acorporation.- of Delaware Original application October .22,1'94-2,Serial No. 463,010. Divided and this; application Aprill.. 1947, SerialNo. .741,525

My kinvention relates to the alkylation of aromatic hydrocarbons witholen hydrocarbons. More particularly, my invention relates to theethylation of relativelyloW-boiling aromatic hydrocarbons,r such asbenzene, toluene, and thek xylenes, in thepresence of a catalystessentially consisting of hydrogen fluoride. This application is adivision of my prior cofpendinglapplication, Serial No. li63,010, filedOctober22, 1942, now abandoned, in which myself: and Louis C. Rubin areco-inventors and `is a continuation-impart of my prior co-pendingapplication, Serial No. 395,973,1"lled May 31, 1941, nowV abandoned. Theprior-co-pending application Serial` No. 395,973, relates rto thealkylation of an aromatic hydrocarbonWithjan-olen in the presence ofhydrogen: uoride as the catalyst, with the catalyst-in either the liquid'or vapor phase.

I 'have discovered thatvlowfboiling aromaticy hydrocarbons, suchy asbenzene, toluene `and the xylenes, can be ethylated'bymeans of a mixtureof'gases consisting of ethyleneand lnon--reactive gases,.- suchasmethane,y ethane, and propane, in the presence of hydrogen nuoride undersuitable conditions. of temperature-andpressura A An importantapplication Yof my inver-i-tionA .residesinthe use of mixtures ofhydrocarbongases produced. by thermal. or catalytic. cracking ofhydrocaubons.- fractionated to separate therefrom the hydrocarbonshaving four carbon/atoms per molecule, which Vare employed in thesynthesis of gasoline ofi -highoctane number and `as `source -materialsfor-other-products, such as butadiene. The remaining portion of `suchcracked gases-contains,- in additionto ethylene and parafnhydrocarbenssuch as methane; ethane, and propane, asub'stantial 'proportion ofpropylene-- In the use or such a4 gas mixture in myprocess as -afsourceof ethyl-f enefferthe ethylation of aromatic hydrocarbons,-

I` prefer ltoremovethe 'propylene in a preliminary step by suitablefractionation or-bysubjecting the4 mixture to suitable reactionconditions to convert-:the propyl'eneselectively to a product Awhichcan-be-separatedby fractionation, Fori examp, the gasmxture canbesubiectedA-to polymer-ization or- Va'llrylation treatment in Vthepresence offphosphorc acid orsulfurc acid to convert the propylene`to--a high-,boiling product whic'ncan be separated easily l,from theunreacted gases. vIwthis*manner the propylene is ,effectively separated#from the gases to be employedv in the ethylationstepg:

In a-` preferred modiiication of myr process, I subect the gas, mixturecontaining Yethylene 'and 14 anims. (o1. acadien) propylenetoapreliminary alkylation treatment with aY suitablearomatic Ahydrocarbonin the presence ofY hydrogen uorideunder conditions adapted to eiiectsubstantially complete reaction of propylenewith the aromatichydrocarbon While substantiallylavoiding reaction of ethylene. Thepreferred modification, of my process, therefore, involves atWo-stepytreatment of the gas mixture, in separate. reaction kzones.with intermediate separation of the liquid products, in the presence ofaromatic hydrocarbons yand hydrogen fluoride.. Thereaction conditionsare4 regulatedrin each zonet/hereby the lqudproduct of thefrst a1-kylation step consists essentially of propylated aromatic hydrocarbonsAand the liquid product of the second ralkylat'ion-step.consistsessentiallyof Such mixtures. ordinarily. are

ethylated aromatic hydrcgncarbons .In the appli-` cation of thepreferred modification of my process to the alkylaton of benzene vtheproduct of the first step consistsessentially ofisopropylbenzene, whichisa valuable ingreb'lient--for aviation gaso-v line because of itshighanti-knock value,rand the lproduct lof. the second'l step consistsessentiallyvof ethyl .benzenev Which also is a desirable motorfuelingredient.; Each of these products, moreover, can .beemployed as asource material` for the production of; styrene by thermal treatment ofthe ,isopropyl benzene and by dehydroV genation ofthe ethyl-benzene.

While the catalyst employed-.in my invention consists essentially of.hydrogen fluoride,- minor amounts of other materials may be'employedAin connection with the hydrogen fluoride as pro-` moters, such. as smallamounts of boron fluoride or nickel. .I preferto carry out the processunder conditions of temperature and pressure at which the hydrogenfluoride is in the liquid state, al though the use of hydrogen fluoridein the vapor form is not excluded from the scope ofmy inven tion.

In carrying out theethylation of aromatic hydrocarbons in accordancewitlrmy process the aromatic hydrocarbon, or a mixture of aromatichydrocarbons, or a. mixture of hydrocarbons containing an ,aromatichydrocarbon to be ethylated, is intimately contacted With a gas mixtureconsisting essentially of ethylene and non-reactive gases in thepresencev of hydrogen fluoride at a temperature not substantiallyV lowerthanv 50 F. and under apressurenot substantially lower than 200 poundsper square inch for a time sufficient Yto eect the desiredreaction ofethylene andthe y values, higher temperatures and higher pressures.

merize, although this eiect is not so noticeable v as in connection withthe use of high temperatures. Pressures up to 3000 pounds per squareinch may be employed without excessive polymerization of the ethylene,although the use of higher pressures is not excluded iromrthe scope ofmy invention. Inasmuch as the speed of the reaction is promoted by hightemperature and especially by high pressure, 'I prefer to employ as higha pressure and as high a temperature as is practical or permissible.

In the alkylation of aromatic hydrocarbons by means of propylene, or anyolein hydrocarbons other than ethylene whichl may be present in the gasmixture, the reaction may be carried out in the presence of hydrogenfluoride at lower temperatures and, particularly, lower pressures thanin the ethylation step. In the propylation step the temperature shouldnot be substantially higher than room temperature and lower temperaturesmay be employed with advantage. The pressure in the propylation stepshould be substantially low-er than 200 pounds per square inch,particularly when employing a relatively high temperature, in order tominimize reaction of the ethylene in the gas mixture. Satisfactoryconditions for this operation are room temperature and atmosphericpressure.

In both the propylation and the ethylation zones I prefer to maintainthe molar ratio of the aromatic reactants to the olen reactants notlower than 1:1. Preferably, this ratio should be at least :1.

The quantity of hydrogen fluoride which should be used in relation tothe quantities of hydrocarbon reactants in each reaction zone is notcritical, but a sufficient volume of hydrogen uoride in relation to thevolume Yof hydrocarbons which are present should be maintained to permitintimate mixing and dispersion of thc hydrocarbons and hydrogeniiuoride. Suitably, the reactions m-ay be carried out by intimatelycontacting the gas mixture, in the gaseous form, with a liquid mixtureof the aromatic hydrocarbons to be alkylated and hydrogen fluoride.Conveniently, the reactions are carried out in the liquid phase in acontinuous manner in which an emulsion of hydrogen fluoride andhydrocarbons including the aromatic-reactants is contacted with the gasmixture containing the olefin reactant. A portion of the emulsion iswithdrawn continuously for recovery of the alkylated product, and freshsupplies of hydrocarbon reactants are added continuously to the reactionzone in the proportions necessary to maintain the desired molar ratio ofaromatic reactants to olefin reactants. The hydrocarbons withdrawn fromthe reaction zone are fractionated to separate hydrocarbons suitable forrecycling from thek alkylated product.

In such a continuous operation the mixture which is Withdrawn ispermitted to settle to separate hydrocarbons from the hydrogen fluoride.The settling operation may be conducted at a relatively low pressure topermit evaporation of hydrocarbon gases contained in the mixture. Gasesthus separated from the products of the propylation stage of thetwo-stage operation are passed to the ethylation stage. Gases thusseparated from the products of the ethylation stage are substantiallydenuded of olefin reactants and are withdrawn from the process. Theliquid hydrocarbons separated by settling from the hydrogen fluoride arefractionated to separate fractions suitable for recycling anda fractioncontaining the alkylated product. These hydrocarbcns may be treated, forexample, with caustic, prior to fractionation to remove residualhydrogen fluoride. Hydrogen fluoride withl drawn from the reaction zonesis replaced by the continuous or periodic addition to the reaction zonesof recycled or fresh hydro-gen iucride.

In either the propylation step or the ethylation step of my process andwhen operating on individual aromatic hydrocarbons or mixtures thereof-or hydrocarbon mixtures containing aromatic hydrocarbons, the reactionproducts may include undesired high-boiling products, such aspolyalkylated aromatic hydrocarbons. For example, in the ethylation ofbenzene the reaction products may include di-ethyl benzene and tri-ethylbenzene as well as the desired ,mono-ethyl benzene. Such high-boilingproducts may be separated from the desired allrylated aromatichydrocarbons by fractionation and returned to the reaction zones forconversion to the desired alkylated aromatic hydrocarbons bydealkylation reactions.

My invention will be described further by reference to specific examplesof the ethylation of aromatic hydrocarbons by means of a gas mixtureconsisting of ethylene and non-reactive hydrocarbons and specificexamples of the preparation of a gas mixture for such ethylation by theuse thereof in a preliminary propylation treatment under conditionsadapted to prevent reaction of the ethylene. These examples involve thealkylaticn of benzene. It should Abe understood, however, that theinvention is not limited to the treatment oi benzene but includes withinits scope the alkylation of any suitable aromatic hydrocarbon,particularly low-boiling aromatic hydrocarbons such as benzene, toluene,and the xylenes. It is to be understood, furthermore, that themodification of my invention involving a two-stage treatment of the gasmixture does not necessarily require the treatment of the same aromaticmaterial in each stage.

Example I I In this operation benzene was successfully ethylated in thepresence of hydrogen uoride un;

der proper reaction conditions by means of a gas mixture consisting ofethylene and non-reactive hydrocarbons. The gas mixture which wasemployed consisted of 16 volume per cent ethylene, 29 Volume per centethane and 55 volume per cent methane. A mixture of 1500 cc. of benzeneand 200 grams of hydrogen fluoride was maintained in a stirring bomb,and the gas mixture was introduced at the rate of '1 cubic foot perhour. The reaction zone was maintained at room temperature and under apressure of 400 pounds per square inch. The stirrer was operated at 400R. P. M. During an operating run of one hour per cent of the ethylenein' the gas mixture passed through vthe bomb was removed. A distillationanalysis of the liquid product showed that 93 per cent of the ethylenewhich was absorbed Was converted to mono-ethyl benzene by reaction withbenzene. A small amount of highboiling product accounted for theremainder of the ethylene which was absorbed. This material,v

could be recycled to yield more ethyl benzene.

5 Example!! this' operation. a. mixture of .propfylene-,.v ethf. ylene,ethaneand n'iethanewasv employed in-:the propylationofl benzene inthepresence. of hydro-- gen:` uoride under conditions'l adapted to.remove propylene `from the lmixture substantially) v.corni-i pletely.The gas: Ymixture. which was employed contained 119 volumeper.centpropylenei anda'f'` volume per cent. ethylene,v .the remainder.consists ing of ethane-andmethane. This; gas..1 mixture waspassedthrough a .mixturev of benzene andthyi drogen yuoride atYatmospheric .pressure room temperature. After the gas.mixture hadi beenbubbled through the reactor it contained .02..per cent propylene and theliquid yproduct;consisted substantially entirely of`propylatedirbenzenes. As was-demonstrated. in Example I, the; remaininggasx` mixture couldl be employed to ethylate;'-bens` zene by theapplication of aihigher` pressure-in excess of 20G-pounds` per .squareinch,. preferably 3001 to 500v pounds per square, inch.

ExampZeHI.

Inthis operation a gas mixture containingfboth propylene andethylene,was .reacted under conf.- diticnsv selected toremove propylenefwithout.substantial reaction ofl ethylene, and to producea propylated .productof high purity. In this op.- eraition .87.5 gramsqof benzene and 20.0grams, of hydrogen, uoride were charged. linto astirring bomb .in whichthe, stirrer was operatedV at. 40,0 R. P.. M. Into. the. bomb wereintroduced overV a period of: five, to six; hours; a .gasmixturcconsisting; of .1.81 grams of: ethylene, 8.5 grams oi prolly'.- leneand.small. amountsof saturated gases., The operation was carriedout; at,Aatmospheric; pres.- .snref androom temperature. Three grams of propylenewere; detected. in.; thev outletv gas. The remaining 82V grams .wererepresented. by `monofisopropyl benzeneequivalent. to 9.6.12l percentofthe theoretical yield. Asmall amount. of. polyisopropyl vbenzene was,also obtainedin-y an amount suicent to`v account. for the remaining3.8per cent1 of the.. ,absorbedipropylena The ethylene passed. throughthe. reactor without. entering into thereaction. The. distillation; ofthe liquid prod,- uct revealed no.. ethyl benzene .-whateyer.. Theethylene appearedin; the outlet. gas or waere,- tained in solutionin thehydrocarbon layen The: inventionwilllbe describedl further by ref.-erence to the accompanying drawingiwhichisa .diagrammatic viewin.elevation of .an arrangementofapparatus for carrying .outthe-:embodiment .ofl the invention in whichthe. rgas mixture 'treatedcontains both propyleneand ethylene 4and i related .paraiiinhydrocarbons, such. as propane, ethane,v andmethane, as well, as othergaSeS-...Sllh as lfrydrogen., which are ordinarily4 found. i111 crackedgases. It is kto bel understood', however,v vthat the invention is notlimited 'to anfoperat'ion involving the treatment of a gascomprisingipropayleneand theA preliminary treatment olisueh a gas toremove ethylene therefrom; It i's-tobe 'understood' further; that in theembodiment of the f invention-invo1vingthe treatment of a gas com'-'prising both ethylene andpropylenethe specifi-c method 10i reacting thepropylene discljosedin connection with thedrawng is not an essentialfeature of the invention, although it is preferred that' in. thismcdincation 'theY generar .method of reacting the0 ethylene be, applied'also Jto the reacfv .tion of thepropylene.

Referring to tl'iedrawing,V a substantlallyjliq.-

miseri 6.. uidmixtureoi hydrogen nutrida. beuzcnecthyl;oe..;ano.low.boi1ing1u 'ranmhydmccrbou eases is..mairitainedpinr.eactol.. Si. ilarlya substantiallyliquidmixture of; hydrogen fluoride,benzene. propylicua, cthylenciandiow .boiling Parafn hydrocarbon gasesis maintained in reactor l2'. Each of these. mixturesis -continuouslyagitated by any ,suitable .means to. intimately mix the hydrocarbons,and hydrogen vfluoride. Such mixing resultsin thev iormation ofw anemulsion4 of the. liquidv hydrocarbons and hydrogen uoride. Conyenientl,agitation is' effected by withdrawinga portion of the mixture in thereactor from an upper. part' thereof' and recycling the mixture thus.withdrawn into a. distributing. element in the lower portionof thereactor. In reactor I` a portion ofv the. Ymixture is .withdrawn throughco1- lectingwmeans 3iandrrecirculatedthrough line 4 into a .distributingelement 5 located. in the lower portion of the reactor l. Line 4 isprovided with apump; and distributing element 5 is provided withvsuitable injection means for introducing the recirculated' mixture in aparallel row of jets whereby the body 'of reactants and' hydrogen uoridein reactor l is, violently agitated and intimate. mixing of' thereactants and catalyst is., effooted'.

Inv operations at relatively low, temperatures the heat 'developedby theexothermic alkylation reactions. may, necessitate the provision of.means forcooling lthe reaction mixture to maintain the reactiontemperature ati'the .desired level'.v To efect suchl Coolingj. anysuitable means for re.- frigeratiue thereacting mixture by indirect.heat exchange may be provided. Conveniently.. cool'- ingy iseff'ectedAby passingthe lcirculated-mixture through cooling;v means '11 locatedin line 4, preferably `beiivizeen pump 6; and distributing element 5.

VReactor 2is provided with meansior, agitation and cooling of thereaction mixture in a manner similar to reactor. l., A portion of thereaction mixture in reactor V2. is withdrawnthererom throughj collectingymeans. 8 and' recirculated through Vline 9,` which connects withdistributing element |10 'located in the lower portion of re.-1

actor 2.4 Line 9'is provided with a pump Ii and cooling. means |11," to,serve the same purposes as pump, Ejand' cooling means, Tin line li.

A reaction .gas .mixture comprising propylenc, ethylene. and low boilinglparaiin hydrocarbons, such asl propane, ethane,r and methane,v isintroducedintothe System through' line @which connects withilines Vand'is. provided with a compressor '3`"fo'r introducing the gS mixture intothe ,liquid'mixture passing through line S at the operating pressure. s

Benzene is introduced in the system through 'line lwhi'ch connects'with` line e'andf'is pro.- vided-with a pump I5.:

Hydrogeniuoride ina liquidi condition is intro.- .duced'into theel/stemthroughV line i6 'whichconn nects with line 9.and` is provid'edwith'apump if?.

The .mixture of. hydrogenv fluoride .andhydrocarbons flowing throughline .9. emerges. therefrom into the interiorof reactory 2 vthroughdis.- tributi'ng .element '.IjEJ. which/is provided with suitable'injecti'on means, ThereSu-lting Ymixturerof recirculated.emulsion.fresh fccdphydrocarbons fresh; ,reactants and catalyst..v and,reactants. and catalyst recycled f ron1 j;h'e operation in a mannertobe. .descrbedbelow,. isintimately mixed, .by .the

injection. means. at. iii .whereby theplopylenc .iin

Areacti; Vt.arcaszts..substantially y.entirely with `ben.-

- 7 4 reactor 2 are regulated to provide reaction conditions under whichpropylene introduced therein is reacted substantially entirelyIwithout'substantial reaction of ethylene. Room temperature, or lower,and atmospheric pressure are satisfactory.

A portion of the reaction mixture in reactor 2, the equivalent in volumeto the quantity of catalyst and hydrocarbons introduced into line 9 fromlines I2, I4, and I6, and catalyst and hydrocarbons recycled in themanner to be described below, is withdrawn continuously from reactor 2through line I8. Preferably the point of withdrawal of reaction mixturethrough line I8 is located somewhat above the collecting means 8 wherebypreliminary separation of hydrogen fluoride from the hydrocarbon phaseof the emulsion may 'be effected in the portion of reactor 2 abovecollecting means 3. In this manner the material withdrawn through lineI8` contains a smaller portion of hydrogen fluoride than the mixture inreactor 2 as a whole. This reduces the amount of hydrogen fluoride whichmust be recycled.

The reaction mixture withdrawn through line i8 from reactor 2 isintroduced into separator i9 at a reduced pressure. In separator I9 thepressure is maintained sufficiently low to permit evaporation andseparation of substantially all low boiling hydrocarbons contained inthe hydrocarbon phase. The gas mixture thus separated is withdrawnoverhead from separator i9 through line 20 which connects with line `iand is provided with a compressor 2l. By means of line 20 and compressor2l the gas mixture separated in separator I9, comprising ethylene, asthe sole olefin constituent, and low boiling paraffin hydrocarbon gases,is introduced into the circulating liquid mixture in line t at theoperating pressure of reactor I.

Reactor I is maintained at a pressure of at least 200 lbs. per squareinch, preferably 400 to 500 lbs. per square inch. Any temperature up tothat at which substantial polymerization of the ethylene occurs may beemployed. A temperature as high as 200 F. may be employed withouteffecting substantial polymerization, particularly if a high ratio ofbenzene to ethylene is maintained in reactor i. The important factor inpromoting ethylation of the benzene is, however, the pressure maintainedin reactor I, and room temperature maybe employed satisfactorily if asuiciently high pressure is maintained. Pressures -up to 3,000 lbs. persquare inch may be employed, but those in the range 400 to 500 lbs. r

per square inch are found to be satisfactory.

In addition to the gas mixture introduced into line 4 from line 20recycled benzene and recycled hydrogen fluoride are introduced into line4. Fresh hydrogen fluoride in an amount sufcient to maintain thequantity of this material in the ethylation reaction system at thedesired figure is introduced into line 4 from line 22 which connectsline I6 with line 4. If necessary, a pump 23 may be provided in line 22to overcome the relatively high pressure maintained in reactor I ascompared to that of reactor 2.

Fresh benzene in an amount equivalent to the benzene withdrawn from theethylation reaction system as reaction product or as benzene entrainedin the reaction product is introduced into line 4 through line 2li,which connects line I4 with line 4. If necessary a pump 25 may beprovided in line 24 to overcome the relatively high pressure of reactor2. The mixture of hydrogen fluoride and hydrocarbons flowing throughline emerges therefrom into the interior of reactor I throughdistributing means 5, which is provided with suitable injection means,such as nozzles. The resulting mixture of recirculated emulsion,including fresh feed hydrocarbons and reactants and recycledhydrocarbons andreactants, is intimately mixed by the injection means at5. As a result of the suitable reaction conditions imposed on thereaction mixture in reactor I, and the intimate contact of ethylene withthe benzene contained therein, substantially complete reaction ofethylene and benzene is effected with the formation of ethyl benzenes,which predominate in mono-ethyl benzene.

A portion of the reaction mixture in reactor Iv is withdrawncontinuously from reactor I through line 26. Preferably the point ofwithdrawal of reaction-mixture through line 26 is located abovecollecting means 3 whereby a preliminary partial separation of hydrogenfluoride from the hydrocarbon phase of the emulsion may be effected in amanner described in connection with reactor 2 and line I3.

The reaction mixture withdrawn from reactor I through line 26 isintroduced into separator 2l at reduced pressure. In separator 2l thepressure is maintained sufficiently low tov permit evaporation andseparation of low boiling hydrocarbons contained in the hydrocarbonphase. This gas mixture consisting substantially entirely of low boilingparafn hydrocarbon gases and other relatively inert constituents, suchas hydrogen, is withdrawn overhead from separator 27 through line 28.rIhis gas mixture is withdrawn from Ithe process for further useelsewhere, for example as fuel.

In separator 21 the liquid materials separate into a lower phaseconsisting essentially of hydrogen fluoride and an upper phaseconsisting essentially of alkylated benzenes and benzene.

The hydrogen fluoride phase separated in separator 21 is withdrawntherefrom through line 29 which connects separator 2r with a hydrogenfluoride settler 30. In settler 3 the hydrogen fluoride is maintained asa relatively quiescent body toV permit settling of relatively heavymaterials consisting principally of complexes of hy- 'drocarbonreactants and hydrogen fluoride.

This operation assists in maintaining the catalytic activity of theremaining hydrogen fluoride at a satisfactory level.

The heavy material separated in settler 30 is withdrawn through line 3|for further treatment in a manner to be described below. The hydrogenfluoride is withdrawn from the upper portion of settler 30 through line32 which connects with line 4 and thus provides for recycling hydrogenfluoride to reactor I. Line 32 is provided with a pump 33 for recyclingthe hydrogen fluoride against the operating pressure in reactor I.

The hydrocarbon mixture separated as the upper liquid phase in separator2 is Withdrawn therefrom through line 34. In Order to remove anyhydrogen fluoride entrained in the hydrocarbon mixture flowing throughline 34 a suitable quantity 0f alkali solution is introduced into line34 by means of line 35. Line 35 is connected to a suitable source ofalkali solution, not shown, and is provided with a pump 36.

Line 34 connects with an alkali settler 31, whereby the mixture ofhydrocarbons, alkali, and neutralized hydrogen fluoride is permitted toseparate into anuppe'r phase containing'thel however,

vtionator I by means of line 52. vided with cooling rneans` Sto condensethe ethyl benzene. Line .52 connects Ywith accumulator drum 54. in whichthe liquid ethyl benzene is'permitted to accumulate. 'Ethyl A benzene,which" as alquid .condensate in fractionator `through line 58.

drawn from the. processfor further handling vhydrocarbons substantiallylfree vof hydrogen uoride V and `a lower alkali phase .containing 'thereaction product ofthe neutralization .of `the hyjdrogeniluoride. Thespent alkali .is withdrawn from settler 31 through line 38.

The hydrocarbon mixture," `substantially -fre of hydrogen fluoride, isVwithdrawn overhead `from .settler 3,1 through line BSL-Which connectswith a fractionator 4E?. If desired, a. suitable .drier 4i is'interposedin line 3@ Vto remove 4traces of water from the hydrocarbon mixture.

In fractionator 4Q ithe hydrocarbon mixture is fractionated into a vaporfraction consisting essentially of benzene .and aliquid 'fractionconsisting essentially of the valkylated benzenes.

VFractionator di) is provided with vsuitablefractionating means toeffect substantially vComplete separation of benzene from the alkylatedbenjqzenes. .The benzener passes overhead as a vapor -from fractionator40 'through line 42. means. 43 are interposed in line `4 2 Vtojcool theVaporized benzene sufficiently to liquefyit. Line 42 `connects withdrum44 in which the -liquid .benzene is permitted to accumulate. l Liquidbenzene is withdrawn from aectunulator drum 44 throughjline 45 whichconnects with line .65. whereby ythe liquid passing through line 45 iS.recycled to lthe reaction Zone in reactor i Line. 45 isprov'ided withapump 46 Ato effect such recycling of .benzene ragainst thepressuremaintainedin reactor i..

A portion of the benzene flowing through line 45 may be divertedtherefrom through line 4l and returned tothe upper portion offractionator 4) as .reflux to assist in the fractionation operation.

The alkylated benzenes, consisting predominantly of ethyl benzene, arewithdrawn from the lower portion o f fractionator i0 .through line 48.This materialmay be withdrawn from the system for further treatmentelsewhere. Preferably, the alkylated benzenes withdrawn through line 4Sare subjected to further fractionation in the system. Forjthis purpose,line 49, suitably provided with a pump 55 is provided to connect line 48with a second fractionator 5i. In fractionator .5I conditions and meansare Drovided to separate ethyl .rbenzenes substantially completely frompoly alkyl benzenes, such as diethyl .benzenes .The ethyl .benzene visseparated roverhead as a vapor and is withdrawn from frac' Line 52 isproconstitutes the principal product `of the process,

is withdrawn from accumulator .drumtllthrough 'line provided with a pump5t. the ethyl benzene flowing through line 55 may bediverted therefromthrough line 57 and rre-A` A portion of turned to the upper portion offractionator 5i as redux.

The poly alkyl benzenes which are .separated El are the lower portionVthereof This material may be withwithdrawn from elsewhere, butpreferably is'recycled to the reaction Zone in reactor i in whole or inpart. 'By

this means the Poly. ethyl benzenes, such as di-Y ethyl benzene, whichconstitute vsubstantially the vwhole of the condensate.withdrawn through`line .58, are converted Vto ethyl benzene by disproportionationreactions, suchas de-ethylation. vFor this purpose, a'p'ortion of the'material'flowing Cooling [line '59.

.uoride .settler 66 through line. 6l.

, sure in reactor 2.. .ing throughline vHi may .be diverted therefromrthrouglfrline 'IB and introducedintothe top of .fractionator 69 asreflux.

f The upper liquid phase Aseparated in separator I9v consistingessentially of benzene, isopropyl benzene and. poly alkyl benzenes, iswithdrawn therefrom throug-h line54. f. In order toneutralize hydrogeniiuoride which may be entrained in material owing `through line 64,alkali-solution .is introduced. Ainto line. 64v throughline 65,

which `connects with line 35. The .mixture ,of alkali .solution andhydrocarbons passes from line. 64 `into alkali settler 65., In settler'66 the mixture. separates into an upper hydrocarbon phase.substantiallyv freefrom hydrogen fluoride,

and a lower alkalifphase containing Athe reaction product -of .theneutralization of the 'hydrogen The-lower .phase is V'withdrawn fromvThe hydrocarbon` I nii'iture` is withdrawn from settler .65 throughlnewhich connects with a fractionator B9. .'Afdrier lflllm'ay .beinterposedinline .l'for removing water entrained in the hydrocarbon .mixturepassing therethrough.

.Operating conditions and fractionating .means aremaintainedinfractionator .69 to erfect separation'overheadof .a .vapor fractionconsisting essentially. of. substantially all benzene in frac- .tonator'69.. .The vapors' are withdrawn koverhead through line 1l and arecondensed by .cooler 12...in,..line Til.v .The condensed benzenepassesfrom line FH intoaccumulator "I3 .from which .it is withdrawn .andrecycled to reactor 2 through .line 1.4, -which connects accumulator 'f3withiline 9. A. pump. 15 'is provided in line'14 in order to recyclethebenzene against .the operating- .pres- Aporton of the benzene flow- .Thecondensate separated in .'fractionator 69, vconsisti ngressentially. 'ofisopropyl benzene and poly alkyl benzenes is withdrawn therefrom throughline 11. Preferably this material is subjected to further fractionationtreatment to yseparate isopropyl benzene from vhigher boiling materials.For this .purpose all or a portiony oi the condensate withdrawn through..line 11 is diverted therefromthrough line 18 which connects line 'Ilwithfractionator 19, and is provided with a pump 80.

,In fractionator 19 operating conditions and fractionating Ameans areprovided to separate overhead a vapor fraction consisting essentially ofisopropyl benzene. These vapors are withdrawn overhead lthrough line 8|and are lcondensed bypassagethrough cooler 82. The condensed isopropylbenzene passes from line 8| to accumulator .83 from which ityis'withdrawn vthrough line 34,A provided with a `pump 85. A

portion of the'isopropyl benzeneilowing through line 84 may be divertedtherefrom through line 85 .and introduced into the `upper `portion offraotionator 19 as reflux.

The .condensate fraction separated in frac- .t'ionator 19,and'consisting of poly. Yalkyl benzenes, 'such as di-isopropylbenzene,is'withdrawn from .settling and Withdrawn through line 90.

fractionator 19 through line 81. Preferably this material is recycledwholly or in part to reactor 2 to effect conversion of di-isopropylbenzene and similar benzenes to mono-isopropyl by disproportionationreactions, such as de-alkylation. For this purpose a portion of thematerial iiowing through line 81 is diverted therefrom through line 88,which connects with an accumulatorsettler 89. In settler 89 heavysludge-like materials, including complexes of hydrogen fluoride andhydrocarbon reactants, are separated by The remaining polyalkyl benzenesare Withdrawn from settler 89 through line 9|, provided With a pump 92.For recycling of this material to reactor 2, line 9| convenientlyconnects with line 14.

The hydrogen uoride phase separated in the bottom of separator I9 iswithdrawn therefrom through line 93, which connects with hydrogenfluoride settler 94. In settler 9A. relatively heavy material consistingprincipally of complexes of hydrocarbons and hydrogen fluoride isseparated by settling. The remaining hydrogen uoride is withdrawn fromthe upper portions of settler 94 through line 95, provided with pump 96,to permit recycling of this hydrogen fluoride to reactor 2. The heavymaterial separated by settler 94 is Withdrawn `therefrom through line 91which connects with a hydrogen lluoride fractionator 98. Similarmaterial separated in hydrogen uoride settler 30, and withdrawntherefrom through line 3|, is introduced into fractionator 98 byconnecting line 3| with line 91.

In fractionator 98 fractionating conditions and suitable fractionatingmeans are provided to regenerate and separate hydrogen iluoride vaporsfrom a heavy residue, which is Withdrawn from fractionator 98, and fromthe system, through line 99.

The hydrogen uoride vapors separated in fractionator 98 are withdrawnoverhead therefrom through line which connects with accumulator |0|.Cooling means at |02 in line |00 cool the hydrogen uoride suiiicientlyto condense it. The liquefied hydrogen fluoride in accumulator |0| isrecycled to reactor 2 through line |03, provided with pump |04, whichconnects accumulator |0| with line 9. A portion of the hydrogen fluorideflowing through line |03 may be Withdrawn therefrom and introduced intothe sired alkylation.

2. In a process of alkylating aromatic compounds, reacting anolefin-containing gas with an aromatic hydrocarbon by vapor phasehydrogen fluoride catalyst promoted by boron fluoride at a temperatureof not over 200 F. at which the .reaction proceeds and at a pressure tomaintain the hydrogen fluoride and the boron trifiuoride in the gaseousphase at said temperature and for a time suflicient to effect thedesired alkylation.

3. In a process of alkylating aromatic compounds, reacting anolefin-containing gas with 12 an aromatic hydrocarbon by vapor phasehydrogen fluoride catalyst promoted by boron fluoride at a temperatureof not over 200 F. at which the reaction proceeds and at asuperatmospheric pressure and for a time sufficient to effect thedesired alkylation.

4. In a process of alkylating aromatic compounds, reacting anolefin-containing gas with a larger proportion of an aromatichydrocarbon by vapor phase hydrogen fluoride catalyst promoted by boronfluoride, at a temperature not over 200 F. at which the reactionproceeds and a super atmospheric pressure and for a time sucient toeffect the desired alkylation.

5. In a process of alkylating aromatic compounds, reacting ethylene withbenzene in proportions of 1 mol of the former to 3-15 mols of the latterby vapor phase hydrogen fluoride promoted by a smaller amount of boronuoride, at a temperature not over 200 F. at which the reaction proceedsand pressure at least pounds per square inch and for a time sufcient toeffect the desired alkylation.

6. In a process of alkylating aromatic compounds, reacting anolefin-containing gas with an aromatic hydrocarbon by vapor phasehydrogen uoride catalyst promoted by boron uoride at a temperature ofnot over 200 F. at which the reaction proceeds and at a pressure of atleast 200 pounds per square inch and for a time sufcient to effect thedesired alkylation.

7. In a process of alkylating aromatic compounds, reacting anolefin-containing gas with a Y larger proportion of an aromatichydrocarbon by vapor phase hydrogen fluoride catalyst promoted by boronfluoride, at a temperature not over 200 F. at which the reactionproceeds and pressure at least 200 pounds per square inch and for a timesuflicient to effect the desired alkylation.

8. In a process of alkylating aromatic compounds, reacting ethylene withbenzene in proportions of 1 mol of the former to at least l0 mols of thelatter by vapor phase hydrogen fluoride promoted by a smaller amount ofboron fluoride, at a temperature not over 200 F. at which the reactionproceeds and pressure at least 200 pounds per square inch and for a timesufficient to eiect the desired alkylation.

9. In a process of alkylating aromatic compounds, reacting ethylene withbenzene in proportions of 1 mol of the former to at least 1 mol of thelatter by vapor phase hydrogen fluoride promoted by a smaller amount ofboron uoride, at a temperature not over 200 F. at which the reactionproceeds and pressure at least 200 pounds per square inch and for a timesufficient to eiect the desired alkylation.

10. The method for ethylating single-ring aromatic hydrocarbons whichcomprises contacting a single-ring aromatic hydrocarbon and a mixture ofgases Whose hydrocarbon content consists essentially of ethylene andparan hydrocarbons in the presence of a vapor phase catalyst essentiallyconsisting of hydrogen fluoride at a temperature not over about 200 F.at which the reaction proceeds and under a pressure not substantiallylower than about 200 pounds per square inch for a time sufficient toreact said ethylene with said aromatic single-ring hydrocarbon.

1l. The method for propylating an aromatic hydrocarbon which comprisescontacting an aromatic hydrocarbon With'propylene in the presence of avapor phase hydrogenfluoride catalyst promoted by boron fiuoride at atemperature not SllbSantally lower than about 50 F. and at 13 which thereaction proceeds without substantial polymerization for a time sucientto eiect the desired propylation.

12. The method for propylating benzene which comprises contactingbenzene with propylene in the presence of a vapor phase hydrogenfluoride catalyst promoted by boron fluoride at a temperature notsubstantially lower than about 50 F. and at which the reaction proceedswithout `substantial polymerization for a time su'cient A 14 vapor phasehydrogen uoride catalyst promoted by boron fluoride at a temperaturebetween about room temperature and about 200 F. at which the reactionproceeds and at a pressure, to maintain the hydrogen uoride and borontrifluoride promoter in the vapor phase at said temperature for a timesufficient to eiect the desired alkylation, the mol ratio of aromatichydrocarbon to olefin being not lower than about 1:1.

HERBERT J. PASSING.

REFERENCES CITED Y The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,933,434 Hofmann et al Oct. 31,1933 2,275,312 Tinker et a1 Mar. 3, 1942 2,373,580 Linn Apr. 10, 19452,399,662 Burk et al May 7, 1946 2,423,470 Simons July 8, 1947

1. IN A PROCESS OF ALKYLATING AROMATIC COMPOUNDS, REACTING ANOLEFIN-CONTAINING GAS WITH AN AROMATIC HYDROCARBON BY VAPOR PHASEHYDROGEN FLUORIDE CATALYST PROMOTED BY BORON FLUORIDE AT A TEMPERATUREAT WHICH THE REACTION PROCEEDS WITHOUT SUBSTANTIAL POLYMERIZATION AND ATA PRESSURE TO MAINTAIN THE HYDROGEN FLUORIDE AND BORON TRIFLUORIDE INTHE VAPOR PHASE AT SAID TEM-